You wont be upset you got the board. On the standard settings that come from Jack I have the 18.1's shooting at 900 on set 9 and then the 16 grains shooting on power 4 for backyard pesting and plinking. I forgot the speed, but it is plenty slow for the yard. And what is nice is that on power 9 I have the 18's zeroed at 50 yards, and this happens to line up for my zero at 30 yards on power 4. So no need to adjust the scope when going from back yard to the field, just the power setting.
Have played with some different slugs and have had great success with the higher levels on the stock settings. Look at flitstacks posts, he has been pushing slugs much further and has been great in sharing his settings